IgG4-related sclerosing cholangitis is a distinct type of cholangitis frequently associated with autoimmune pancreatitis and currently recognized as a biliary manifestation of IgG4-related disease. Although clinical diagnostic criteria of IgG4-related sclerosing cholangitis were established in 2012, differential diagnosis from primary sclerosing cholangitis and cholangiocarcinoma is sometimes difficult. Because the evidence level of most retrived articles was low (below C), we developed consensus guidelines. Three committees (a guideline creating committee, an expert panelist committee for rating statements according to the modified Delphi method, and an evaluating committee) were organized. Eighteen clinical questions with clinical statements were developed regarding diagnosis and treatment. Recommendation levels for clinical statements were set using the modified Delphi approach. The guidelines explain methods for accurate diagnosis, and safe and appropriate treatment of IgG4-related sclerosing cholangitis.

In the past year, we evaluated age-related changes and setting an upper limit of extrahepatic bile duct diameter (EHBD) with considering the presence or absence of cholecystectomy in 2265 individuals who had routine health checks or abdominal ultrasonography without abdominal symptoms. Sixty-nine of them had undergone cholecystectomy. EHBD was measured from the front of the anterior wall to the front of the posterior wall on ultrasonograms. The mean EHBD of all subjects and no past-history of cholecystectomy group increased with age except for individuals in their teens, nineties and centenarians. The mean EHBD by gender also increased with age, except for males in one teen and females in nineties and one centenarian. In individuals who had undergone cholecystectomy, the mean EHBD showed no age-related tendency to change, although there was a tendency for increased dilatation in each age compared with non-cholecystectomy group. As the age-related change in EHBD shows no relation to gender, there is a need to establish a reference value for EHBD in each age group while bearing in mind whether or not there has been past-history of cholecystectomy, in order to judge appropriately whether the bile duct is dilated.

This study aimed to elucidate the significance of combined vascular resection and reconstruction (VR) in surgery for locally advanced perihilar cholangiocarcinoma (PHC). Eighty-one resected PHC patients were divided into three groups: non-VR (n=37), VR of portal vein (VR-PV: n=25), and VR of hepatic artery (VR-HA: n=12) Preoperative CA19-9 levels of both VR-PV and VR-HA groups were significantly high compared to those of non-VR group. There were no significant differences in rates of morbidity and mortality among three groups. In pathological findings, although both VR-PV and VR-HA groups had a significantly higher rate of advanced tumor (≥T3) compared to non-VR group, there were no significant differences in rates of lymph node metastasis and R0 resection among three groups.

Although 5-year disease specific survival (5-year DDS) in VR-PV (29%) and VR-HA (25%) groups were tended to be poor compared to patients in non-VR group (42%), they were significantly better as compared to that in patients with unresected locally advanced PHC (5%). It was considered that VR in surgery for locally advanced PHC was feasible and useful.

Endoscopic ultrasonography (EUS) has greater spatial resolution than other types of diagnostic imaging modalities. In addition, if gallbladder lesions are found and gallbladder cancer is suspected, EUS is an indispensable modality, enabling detailed tests, using the Doppler mode and ultrasound agents, for invasion depth diagnosis, and so on. Furthermore, with gallbladder lesions, EUS combined with fine needle aspiration (EUS-FNA) is available for distinguishing between benign and malignant forms of conditions such as xanthogranulomatous cholecystitis, and collecting evidence before chemotherapy, and is useful for a highly precise and specific diagnosis. However, prevention of bile leakage, an accidental symptom, is highly important. As a result of widespread use of next-generation sequencers, there have been reports of driver genes even in biliary tract cancers, including gall bladder cancer, and clinical studies are now being carried out on molecular therapeutic agents targeting these genes. It is considered that gene-panel assays using next-generation sequencers will be feasible with samples obtained by EUS-FNA, further increasing the demand for EUS-FNA.

Incidence of gallbladder cancer is gradually decreased worldwide. However, there are still a lot of patients who are diagnosed as having late stage disease. Several potential risk factors have been reported, such as regionality, ethnicity, sex, gallstones, bacterial infection, obesity, diabetes mellitus, pancreaticobiliary maljunction, adenomyomatosis, smoking, chemical agents, red pepper, heavy metal, etc. Regional distribution may be due to a combination of ethnicity, dietary habit, and living environment. Cholelithiasis is the most significant risk factor. Not only the size of stones and long-term duration of gallstones disease, but also so-called 'thrifty genes' polymorphism which associated with biosynthesis of biliary cholesterols may associate with high risk of gallbladder cancer. Clinical significance of prophylactic cholecystectomy in purpose of early detection and prophylaxis of gallbladder cancer in patients with multiple risk factors should be confirmed after further accumulation of studies.

A woman in her sixties was referred to our hospital with suspected CBD. Enhanced CT and MRCP showed a fusiform CBD of 18mm in diameter. We made a diagnosis of Todani Ic CBD. As she denied consent to ERCP, we were unable to detect the pancreaticobiliary maljunction (PBM) preoperatively. We performed intraoperative cholangiography repeatedly and identified the PBM. We then resected the extra-hepatic CBD from the circumference of the hepatic ducts to the proximal superior of the pancreatic bile junction safely. Recent advancements in image modalities have enabled us to diagnose PBM without cholangiography, but in our case, intraoperative cholangiography was the only way to diagnose PBM because the papillary sphincter extended immediately inferior to the circumference of the PBM. Furthermore, repeated intraoperative cholangiography was useful to resect the biliary tract safely.

A 79-year-old man developed an epigastric pain and a fever during his hospitalization for acute exacerbation of chronic heart failure. Increased hepatobiliary enzyme level and inflammatory reaction were observed. A hyperdense area was detected in the gallbladder and distal bile duct on abdominal computed tomography (CT). Under the diagnosis of acute obstructive chalangitis, endoscopic nasobiliary drainage was conducted. At a later date, dissipation of the hyperdense area in the distal bile duct was observed on abdominal CT. High concentrations of amiodarone and its metabolite in the bile were believed to cause obstructive jaundice. Owing to the necessity of continuous internal administration, endoscopic papillotomy (EST) was conducted for the patient. Subsequently, no recurrence of the obstructive jaundice and acute cholangitis were observed. As no case of obstructive jaundice and acute cholangitis caused by amiodarone administration has been reported in Japan and EST is believed to be useful for the prevention of the recurrences of the aforementioned conditions, we report the outcomes of our case herein.

A 60-year-old male was hospitalized due to jaundice. Contrast-enhanced abdominal CT showed stenosis of the lower bile duct and dilatation of the intra- and extrahepatic bile ducts, and the wall of the lower bile duct showed thickening and marked enhancement in the late phase. ERCP showed severe stenosis of the lower bile duct. Biopsy of the lower bile duct led to the diagnosis of squamous carcinoma. The diagnosis of adenosquamous carcinoma of the bile duct was made, and pancreatoduodenectomy was performed. Histopathological examination revealed that the vater papilla side of the lesion mainly consisted of squamous carcinoma, the center of the lesion exhibited a mixed squamous and adenocarcinoma, and the liver side of the lesion predominantly consisted of adenocarcinoma. Comparison of cholangiography and histopathology findings revealed severe stenosis in the area of the squamous carcinoma. Preoperative diagnosis was possible by biopsy of the lesion mainly consisted of squamous carcinoma.

Case 1 involved an 84-year-old female who underwent endoscopic retrograde cholangiopancreatography (ERCP) with placement of an 8-Fr, 10-cm straight bile duct plastic stent for gallstone pancreatitis with cholangitis. Although there were no symptoms, duodenal perforation by biliary stent was recognized using computed tomographic examination after 2 months. The stent was endoscopically removed, the hole was closed with a clip, and the patient was discharged. Case 2 involved a 93-year-old female who underwent ERCP for choledocholithiasis. Because it was difficult to remove the stones, an 8.5-Fr, 9-cm straight biliary plastic stent was placed. Although there were no symptoms, the biliary stent perforated the duodenum when the scope was inserted for stone removal after 5 months. The stent was endoscopically removed, the hole was closed with a clip, and the patient was discharged. In both the cases, endoscopic treatment was successful.

A 69-year-old man with jaundice was referred to our hospital. Computed tomography and magnetic resonance imaging showed thickened and enhanced bile duct wall in the distal bile duct. Brush cytology in the distal bile duct showed class III, and surgery was performed because of suspected cholangiocarcinoma. Subtotal stomach-preserving pancreaticoduodenectomy plus partial transverse colon resection was performed. The resected specimen revealed a 6 cm × 3 cm tumor that almost extended in the bile duct, from the papilla of Vater to the hepatic-side resected margin. Hematoxylin and eosin staining revealed that the tumor consisted of carcinosarcoma, adenocarcinoma, and squamous cell carcinoma components. Immunohistochemical staining was positive for AE1/AE3, vimentin, and HHF35; therefore, this case was diagnosed as bile duct carcinosarcoma. The patient took S-1 orally after surgery, and he is alive, with no recurrence for 42 months. We report a rare case of a patient with bile duct carcinosarcoma with long-term survival.

We report a case of right ligamentum teres hepatis detected in emergency cholecystectomy performed for acute cholecystitis without cholecystolithiasis. A 51-year-old woman with a complaint of upper abdominal pain underwent cholecystectomy for acute cholecystitis without cholecystolithiasis, starting with the normal four-port method. The neck of the gallbladder widely adhered to the gallbladder bed on the left side of the ligamentum teres hepatis, and the body adhered to membranous tissue on the right side of the liver. We diagnosed the case as acute cholecystitis with right ligamentum teres hepatis. Because a direct approach to the neck of the gallbladder was difficult, we exfoliated the gallbladder normogradely from the fundus. The cystic duct was separated and resected after cholangiography. In this case, a gallbladder bent in cervical part and the wall of the body-fundus thickened it in edema from this part markedly. The postoperative course was good. It was suggested that the gallbladder bent it for right ligamentum teres hepatis case by attachment site of gallbladder and might become cholecystitis.

Gallbladder hemorrhage is a life-threatening condition that is rarely reported. A 69-year-old man was admitted to our hospital with abdominal pain and vomiting. Laboratory data showed an increase in inflammatory markers and deranged liver function test profiles, therefore indicating severe obstructive jaundice. Ultrasonography and computed tomography (CT) scans revealed the presence of blood clots in the gallbladder and common bile duct. The patient was diagnosed with gallbladder hemorrhage. Endoscopic retrograde cholangiopancreatography was performed, which revealed that the blood clot discharged through the Vater's papilla. The blood clot was successfully drained with endoscopic nasobiliary drainage. Cholecystectomy was performed, resulting in rapid improvements in the patient's clinical condition and liver function tests. Histopathological examination of the gallbladder showed necrotic cholecystitis. There have been 39 cases of gallbladder hemorrhage reported in Japan. Gallbladder hemorrhage can be fatal and requires urgent treatment. Good prognosis can be expected after cholecystectomy. We suggested that if the patient is medically fit for surgery, surgical intervention should be the primary treatment. In cases when drainage is required, endoscopic nasobiliary drainage is recommended.

As US is simple and less invasive, it is widely used for the mass screening. However, it can be difficult to visualize the entire biliary tract system due to complicated anatomy, obesity and overlying gas.

The left lateral decubitus position is suitable for visualizing the total biliary tract system and both the high-resolution US and magnified images are essential to detect small lesions.

As for the gallbladder, management of artifacts including the reverberation and the side lobe is a key issue. Gallbladder lesions are classified into 3 types including pedunclated, broad based and wall-thickened (flat) types. This classification is important not only to make a differential diagnosis, but also to evaluate the depth of cancer invasion.

To trace the total course of the extra hepatic bile duct (EHBD), the probe should be moved as if we are writing an inverse letter C. Furthermore, abnormal US findings of the gallbladder, which include impaired fullness and distension with debris, are also useful to detect occult lesions of the EHBD.

The progress of CT and MRI in recent decades has been remarkable, and their role in the diagnosis of biliary tract diseases has become very important. Regarding CT, spatial resolution and time resolution are improved drastically by progress of multidetector - row CT (MDCT), and it has become possible to evaluate subtle changes of thickening or enhancement of bile duct and gall bladder wall. Spatial and time resolution are also improved for MRI, and the impact of the development of MRCP and diffusion weighted images has especially been remarkable. However, the sort and number of images are becoming enormous, which makes it very hard to look through all the exams one by one in order. For image interpretation, there are some important images for each disease, and there are some tips in interpreting them. I will explain the roles of CT and MRI in the diagnosis of biliary tract lesions (choledocholithiasis, polypoid and wall thickening lesions of gallbladder, bile duct lesions) with some tips and pitfalls.